I Built 50+ Free Online Calculators — Here's What I Learned

#productivity #showdev #sideprojects #webdev

I just launched CalcHub Pro, a free collection of 50+ online calculators. Here is what it includes and what I learned building it.

Live Site

https://calchubpro.netlify.app

What Calculators Are Included

Finance: EMI loan calculator, mortgage, compound interest, ROI, break-even, profit and loss, savings goal, inflation, depreciation, VAT, and loan comparison.

Health: BMI, daily calorie needs (TDEE), body fat percentage, sleep cycle calculator, water intake, calories burned, 1-rep max, and running pace.

Math: Percentage, discount, GPA, area, volume, and quadratic equation solver.

Science: Temperature converter, Ohm's law, force F=ma, density, pressure, and wavelength.

Engineering: Electricity bill, concrete, beam deflection, pipe flow rate, and power calculator.

Every day: Fuel cost, tip calculator, screen distance, pet age converter, and overtime pay.

Key Features

No sign-up required. All calculations run entirely in the browser — no data sent to any server. 50 individual calculator pages, 50 guide articles, and 100 blog posts. Mobile-friendly and fast.

Tech Stack

Pure HTML, CSS, and JavaScript. No frameworks, no backend. Hosted on Netlify. Every page has Schema.org structured data, canonical URLs, and unique meta descriptions.

Why I Built It

Most calculator sites block the actual tool with ads, require sign-ups, or load slowly. I wanted something clean, fast, and completely free.

What I Learned Building It

Each of the 50 calculator pages needs a unique title, meta description, and structured data schema. Internal linking between related calculators matters more than I expected for SEO. Getting a sitemap with 219 URLs properly submitted to Google Search Console is the most important technical step for a new site.

The hardest part was not writing the calculator logic but making sure every page was discoverable. A new site with zero backlinks takes 6-12 weeks before Google starts showing impressions, regardless of how good the technical SEO is.